SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbc75206c7a9b129006a49e6ed9bd333ebb931f113dc5e11aafad36a761027d8' 
  AND token = 'e3N25/uU+MrnffgcADJbjLB4RKz9T0ByXLwVh9uYtuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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