SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8ade75d90c3afe1bcf12457506c2da1692ccb23845f0e00646a02d9eced156d' 
  AND token = 'kNVTzQ3ihwVTvL6a+lR0Oyxw+HBWLf/hK1pOJqB4VHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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