SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '635f84b179c741e4bd2d7be309497dd4ecf519d5f8542458a09941250601b2dd' 
  AND token = 'HSf8ZDQBuwle0YThQ7STYsFyrqqtdGKYawyMHCOLRdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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