SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fc66770e52666b888ba8b154f1831316de60cfe7763a21fb7f8a36338282979' 
  AND token = 'WFF2tdEKyUW3sou0anYKEy9Wx11J4fPtg7LBNLaQzt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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