SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '906f68ee21937e4b8b04935911306739cd9aa35782f9b8477733556ff4fda150' 
  AND token = 'RSmuRHLB6KEtkDa4LiUq3dtfD7PmvrJM2lslE9+Rixs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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