SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b6041f40d3928a80cc9d75554774a02ba63a1bdead13964a69fafcb227b2a1c' 
  AND token = '/tlsOc9NOThoBM3wCf3zjXC6qKIGAI7JEPYbEU8Or7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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