SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4548ac8f5fde9521c0fa39414dacf178e931941c18f3afeade5dbf281a11ba24' 
  AND token = 'e7WVw8MHh7qQ7MjegzS8CPKRbP+gDJGfnL2QP9PLJeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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