SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6adc9bb399778d8f524d1517b980c795d19608ccb07c7b922aecbb06b312e3d7' 
  AND token = 'JVVUFJBMrR2GbXLQwgjQ5a/p6hTaC6ZaZxcxKs2Tssg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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