SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3ff378bf8c34defc8ec450dbea0a16d073d48fe5640066e6a0b211ac706e1cf' 
  AND token = '5k1AzKPKZfN9fHQuIHAcjpHrHVFDO9s0n324HI7Xhlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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