SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4e3298a30b34e0a632f9cd4331bef9d278627ba10041d7149585dddb2f05217' 
  AND token = '+DS+mIFhveZpT+O3yZVBGLGvjJVUhu4UXtdBlzZ+Sks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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