SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '418e31acbaca2625df2fa24187fce6563359f56cdbcec8821783f1068126ed55' 
  AND token = 'r3aUxlVKXn2xg6f/rq7eU7qTQYTC0M+TbWZR/cXMmJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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