SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff6d14477745af3fc12fc92411b74392d7199bca6ee14b890addae947b07bf5c' 
  AND token = 'nettKxJf058W8r8ML3SmMlxBif56wPtoxJkJTjO0GHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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