SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1308bfd0eff9bfc2dc1dc8bffe75268fc9107e4fa43714835a341f4654da10d' 
  AND token = 'KixumGel0rCxUeHkhPR+RsjYZUwMTAdHsBpLVfL4G7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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