SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '860816c248e68092e2bb985f80e680fe8e69550622425d2f26c8cef1fa3f4df4' 
  AND token = 'J6mdXTo0+OBy7+BFj+DS94lnCn5wn82GY6o9phUScfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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