SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c483049daa08a2dce7baeed99f54f98b2dcfea404bd59511aa23739f344750d0' 
  AND token = 'W3oCaVSkPtpi/OYettDngV9CWxxz18KTkNI9SvEoopE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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