SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcc5aeb4088cb7cb2db097f77e44b1890c1c6c3c6c84112a9b33486885e8ee61' 
  AND token = 'mscsLQKuqfA0TuxDBjQBjvyiUL9VEQ+KZYhDNxOAjHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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