SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6be3de18efdbd2d306a0f50234e6b2ff3302d836dd58df7a4814ead7e6c67ea9' 
  AND token = 'DfxXKLxPvnfk9UGS08x/ywNGeoRXpEmlIfxjXaZFxUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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