SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38bdbdc35d6e47966eed8d0874aea02ac9c2719f614dd364970d570182b96d74' 
  AND token = 'usJm35vkWNIutFZWVDmlQXL10kOH/2NrRBMZgMP3brk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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