SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0b88e9775775e0fb86bc9bf80277b873ddb0e0e9c811767dc5175fa41bcb349' 
  AND token = 'K6XPJTCOKtXvZ10fMTNXvR4jpMicsfQe/7il9um648c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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