SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a25fcef1362905147048cc12145d096bd9616b0ab42bd3ad35c6e7571d8ab57' 
  AND token = 'vfolkk3mKY+utxrug4oXOEI+MTWPhDvyF7U2D4EcUpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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