SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a768bbc74d57ea612916384c67d193bfcafa4afbc98a5e99bdebde4f4e86a86' 
  AND token = 'fpTNcHw96ws6YCEGH0Lokv7LPpjDhruZpEt/EvGP4PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}