SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb571a0856d858ac971b69cdc4f23fe4e64a0282e4340615611a28eb2074beab' 
  AND token = '6mCmtBMMZZ1ayLdUYkIqWLlLqQkYUoRswZ0ZgAusk+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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