SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1241565844f93dc5db65a32aadf3dac68d871f57483ec2796c4df7d347340402' 
  AND token = 'NMrCTo7FGHW+9TrTlI+/FvCsAVs1tarmqc8/FBRcO5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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