SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8ed3d7def9425a6baade0a60a415d4f744b677caa2aa7750964fa7faec0a87a' 
  AND token = 'zNW1KUFndE96j/UgePvmMARCyrR68Pqm8crKUQ9JlYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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