SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac8a80461c18b244e775224b825d808ead7391ebeaa7ffc510184560c9243667' 
  AND token = 'uAztbRAemRveu/Uv9YR5J3zd4PR8gIIF3jIBhkGPaQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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