SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83f03eec178f5e3cb9d75d80215bb5118ad1a7fab8d804f9a2f5abd22f1c9e32' 
  AND token = 'lga7DMn2XMsISuDVpStJW4dyVOrvZ+rX2hjvlf+IofI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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