SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81a1e3132064fe9bb545c8f0209235cdbb5a489686ec6803880f814733c59368' 
  AND token = 'DCl187h2xxi4kh/ImSW7Q3HAsazhoHEZQrPdJGSarOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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