SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0512323bb4e244b51b9aa49a0d38a68ac72b090a5d4434dfbe2d1c96ffb848b2' 
  AND token = 'BiGlmKxk+Fa1DgW0bKgbF+BYLLZsEtuwPd6wyV8qmrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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