SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b9fdb37286aeee02b095a8ac1018acb91531903d65932bd9598b11134309a12' 
  AND token = 'bid3ZxRqibjoMTEPmmeiN6GAOPnKFqu13TO8Z/StfNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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