SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc65ba24c9f6d4afb423732c1395372f84fa9ab6867beeb49066e6d064671f4e' 
  AND token = 'ib9ZI23CxiVh407ShmtH1uhgyr3192HE945LMdekrQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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