SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbc1536eb16762df3acc6e367587f8c8233c505cd1b525fdf301a8ae8159d4af' 
  AND token = 'VKjiD1isoBH/ZTvOFjWhUua4tXPvYCuA/T4em+d4sQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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