SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dea3fc42fb6a013e4beff559cbe607112c6e2b0db0a2987bfd041457ed140e7b' 
  AND token = 'VqZyFQWesvKse9g8U0kPK8LNDm37+jnnIIkVhNTGmP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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