SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7c808af21fd45288a90435edb8dbed82794303fe16c8cffae83437543bf74d7' 
  AND token = 'nPXFMMDqBKv97vhgAv+2s/rt1ohpDUVtxcf+aO3ceuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}