SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec64959d8f434db536db1253b2fbaddb110f1dafd3be9e6b81ca6686ea6b890e' 
  AND token = 'nrJYxdGRjSBPLbATZt4h+cqOSMVKpcKksC1ES/DWgOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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