SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8af3811f7f02514d24555716eec39494f91323f47c862a87b3832319538753b2' 
  AND token = '7B5KVAsXNO6cBw8pBayMlLMsVKRcI1y/sd1i6iEb/NM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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