SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65a3cb217003e9545101ccecf2f370598a7500e4866683172ac601ead52a2015' 
  AND token = 'Q/am86/w2enYz0pj47xXtyCr0VDnmyemzGvYdcvJG3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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