SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '537a1b19b67659c42a4179a1cc435bf8d4c7fadda014f3969ebd6dc6bda8b7d3' 
  AND token = 'lRKWTcq2NjqhrvaoDTelNGCRryPFNzsUKcYVV7FUdp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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