SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '218aa62495068228fbdb6031615563b7fa068d5c5dc804c335dcd8c9f8f98a57' 
  AND token = 'LAZ3ms44RFlKvSJfqsBbxJS0GABHjrZ6r+N1OC6OtTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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