SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '695ccb639af058d42aa9c1841858b0d458a351208f6c3230fdf618d1f3779fd6' 
  AND token = 'wMus1qpPUmGbOyMN4J+ZISw8L+Ub9QWRpJVtM9KGM2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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