SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47a8f8fc40870bb8adfa60ff7bbcbfc2339890578b4b5460e30de5ba04373d25' 
  AND token = 'xMmUKQzF51xnhIyvCSsz71nwKRDPV14yALPCikvCbj0=' 
  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"
    }
  }
}