SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61efa4891252732425d2becca4aea191f6f7aa92c845804b80fe8850cf902206' 
  AND token = 'zSY6CMsa5siHM6tOOl1olFrAhTrt5Y6V+xmPVAoyiJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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