SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ba7df546336a96b364c938d82fcd959993bdb42bf46cf5a731a47ec2aadb7f9' 
  AND token = 'Gb/uEL6hT8mi2YBB0tdLRYvh/WYGsMumrmJ9xCVMono=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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