SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4a3ce89c6f721aa67c3af5d0b77b9c954386212f86bbeff19d760557be5a806' 
  AND token = 'MahN/iJRilhsIxwUc11xzm3xSfjx10mnrr3IaPsTObw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}