SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9911725d9e70527a2189599b75c19e7ee12a094a34ff03836f6ec81f5b7051b6' 
  AND token = 'xC3//8o+KZWVYkts94E//vOtny6hjQwOxmXVeOuip4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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