SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1a16a2abc35caa9c59e621edb24025bc0a584f3d7348039b71946ad928cf7f3' 
  AND token = 'ROVqqwbTL4O5SGjm1Wz9grQB18+3mVAyUtYbo+6CTtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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