SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2fec885f647a0a7e6f696fc0126cde22a3a465338aca03d7f6eab84118ecb24' 
  AND token = 'KZo++jIUvWljgdzNGmClbBNhPvCVoTp48bRTlp8fyz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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