SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74994d893295322fd2030154a09535d3a65c287952c14a0e7262ae0d51b536f9' 
  AND token = 'enhjbUoYvwKSW3+3hKgdQm/fHM6TCywyTunrYDjwXNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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