SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4142a321e3235451657b0b53134471407a0cf46d3cbdef4cbb18254ff143ab2f' 
  AND token = 'ZtQZM2bOp990aJVf6u2F00TOyk6jQa58+XHkO/ghiag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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