SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6f6982b4ada7bcb37ea3105656e0157e00ccbcef42dc31b26990effbeff241b' 
  AND token = 'I7kSOLlm6nwsgJFLCpNRF0T419g6WMb0MakqSe6rOx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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