SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '195c3d8ce818bec9776e6cfbdd4d69673d4f76a430fa62a076d83d6d91f440b6' 
  AND token = 'ItPWLLXy504v3jqaHoru2Lw5uBgHfFtQkfUURpt5Hl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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