SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cb55dcee485bdcdb69d5b19f86c7499ff1acbf70887a08060675a34bd3a84d9' 
  AND token = '4WYsSoOCAOlSLolI4I2KIxhoy8VXXT48PKB7nFAF8i4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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