SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b963568d85af9ee3c9aae6f552b12d2c602c924f5f66b0afc425ff497f63538b' 
  AND token = '87FalKMOUb36WseQGK8IhtMErkecaiFWlpZ4JqOzC1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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