SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcd6a03790220aad1c85bff8833a693da3f43fac1d02db86fdc228769e988239' 
  AND token = '0S/DzQ90OmsKb/RmXndYAkXTHyGmzl6aTjCNBzajUi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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