SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd40875e06dd42399684e266c3240fe1c5db16934425a6a8465dcf896d04b959c' 
  AND token = 'TxhZyw7QSevBw2M6wPOILL8wXugurDchcu3pP1muM1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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