SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc9b35646ce51dfa02f7b72616b2e78f2c31a9f597f4a106d76dc8f783937803' 
  AND token = 'KlLrPLVqJj9Zh37oivLl3aqOkYcYWUzKgmy3kd1fuB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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