SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2317b199f2aea7cb928314a75439254617f33e5362bf4ee8012820ef39aaac98' 
  AND token = 'B2gjmGl0QYrSt4a1Qh3WvOKIkjFbFP3NHe6JRmX1h/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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