SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f91a4801cf94a60ca7478d6eb118231345f0ce042df55d5e5469b0a7c004e566' 
  AND token = 'NEq8oJmWTsfBzyAUoQmSbI0NI5qHDdoAftFxEaxusvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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