SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e668d21367e77b078c1906db767fb1e89afef6be8fea649793c3b3f2672af706' 
  AND token = '1vXeg/giNPUVNmbPmw/ZCT1Jlgzhox3LCn8wA/tp21U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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