SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71f31549468d8f7bc5f88505ed28ffc7c89d6ee0cd5d972c3e86434fffa9b695' 
  AND token = 'uLoMBAvPJkHX5ptSMiDJChExq2P3nCl+Ssx2gKjo3j0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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