SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '403db3bf697f5786c65b2d22c9eda7d4da6a299bc0873cce1aa4a3de319fadee' 
  AND token = '293teJdSKam5umpPDUW4MONfxtrrrADFi8uOaHlKGrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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