SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdf86f8e1de51f75b4854e594a1fb640164aa29995a67595f34cb13fcdb12fe1' 
  AND token = 'ZaHLeiGkdwTOZ1AobeHvLxInzFOIeymPlha/DhRIXFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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