SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '987799d54fbe6c9591a02d4d91413feb88f8a471f697b4210274b3a457b54e26' 
  AND token = '/QPvLIlvArqRaeLrz7yJh3Arg3ylHs50LYCUk+psVlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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