SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '021cf7f9d3f60fb3f5216f8ccb7f787ce49198ced67ba4615c66c672bc3d4dd5' 
  AND token = 'JAvaWry+c5xSLB0u1FStOM3WYWLRSJiZL8oUWh3UAnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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