SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b7d74da440894f5e23897ea7718c1f01fa1cf7036832c71c77b5ba19f1fb800' 
  AND token = 'KjG3ezka/Ayrtm5SlJoaCP3TD3c26kLMEvtXLB+v/4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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