SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74a46a2a57dae55a1405ce9cb42cf717878384b047db9bab8a4bbfeba16a2036' 
  AND token = 'E+obdexxK+5tS+3RtwlhUpaNtJPdBcufaAtM+FVmBdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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