SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '352d62b1b2c7018985a8313d887d1c6488bc6254b867f2f8a82f238be584caeb' 
  AND token = 'vEc0Z2KFmc898/zdZo2z3MYb6LG5VtI3VZ4Z8yX1spc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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