SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f02a8a91c8e484af79f53d331232ca9a8772669d8328ed1410daadd2ff61fda' 
  AND token = 'QcXt3kGR69fID8WukLjZRJRxhBXQzWG6gyrdp/ogEWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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