SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83a35d56f144e60952c79add190421efcece06ccd55700dfb5cc4be936a5be73' 
  AND token = 'NTQWqGHdrX32KL7/u66ZK221ySY5efUcIvJCNSXCAWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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