SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15cb69aec94ba96829a01458b03d303b50d89dfadd31acf7eb0c47d20429b200' 
  AND token = 'ZCfkbZvbUmwaexaAE/XksHEm0TPw6pO/laPvQHGe2rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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