SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abd948c3c4a6de760224aea20bf6277af0d3703b5d9eda018ae3a40043688f8b' 
  AND token = 'GaMBV+dCQz38tVwr/zcUpsyXVZovPl+F2DoPDxpGKKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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