SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9f076f2df467c186de98ce74b78d8a8238af1314e23cca685368541cc7a6471' 
  AND token = '+bFmDhQSZb16KpkdR8DbN4Qf2r3Q5Iuv2sVPmObjUJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}