SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b38e61eb350cbed32e2741f9c845a20746681b083adf6fdd13255a85dd0f16d' 
  AND token = 'vhxMNxSHOQAoYkDVY5UGhFPPwIt/Krg2KPh3+BpTzks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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